In communications networks, there may be a challenge to obtain good performance and capacity for a given communications protocol, its parameters and the physical environment in which the communications network is deployed.
For example, radio link systems in some communications networks are designed as Frequency Division Duplex (FDD) systems. In FDD systems the transmitted carrier frequency differs from the received carrier frequency. The transmitted signal is commonly at a much higher power level than the received signal. Hence, the receiver of a radio transceiver device operating in a FDD system would saturate if the transmitted signal of the radio transceiver device would leak into its receiver.
A diplexer filter (also known as a branching filter) is commonly used to prevent the transmitted signal from leaking with high power into the receiver. Such a diplexer is relatively expensive to manufacture, and constitutes a quite space-consuming component. Furthermore, FDD systems used for providing microwave links are manufactured and sold for many different frequency bands, and it is therefore necessary to have at least one specific diplexer per frequency band, due to the frequency dependency of components. Hence, the diplexer is commonly designed in several variants (many per frequency band) leading to high cost due to the diplexer as such and the variant penalty cost. There is thus a need for a less complicated mechanism for preventing the transmitted signal of the radio transceiver device to leak into its receiver.